Dynamics of motor nerve terminal remodeling unveiled using SNARE-cleaving botulinum toxins: the extent and duration are dictated by the sites of SNAP-25 truncation

Nerve sprouts emerge from motor nerve terminals following blockade of exo-endocytosis for more than 3 days by botulinum neurotoxin (BoNT), and form functional synapses, albeit temporary. Upon restoration of synaptic activity to the parent terminal 7 and 90 days after exposure to BoNT/F or A respectively, a concomitant retraction of the outgrowths was observed. BoNT/E caused short-term neuroparalysis, and dramatically accelerated the recovery of BoNT/A-paralyzed muscle by further truncation of SNAP-25 and its replenishment with functional full-length SNARE. The removal of 9 C-terminal residues from SNAP-25 by BoNT/A leads to persistence of the inhibitory product due to the formation of a nonproductive SNARE complex(es) at release sites, whereas deletion of a further 17 amino acids permits replenishment and a speedy recovery. (C) 2003 Elsevier Science (USA). All rights reserved.

Incorporating nerve-gliding techniques in the conservative treatment of cubital Tunnel syndrome

Objective: To discuss the diagnosis and treatment of a patient with cubital tunnel syndrome and to illustrate novel treatment modalities for the ulnar nerve and its surrounding structures and target tissues. The rationale for the addition of nerve-gliding techniques will be highlighted. Clinical Features: Two months after onset, a 17-year-old female nursing student who had a traumatic onset of cubital tunnel syndrome still experienced pain around the elbow and paresthesia in the ulnar nerve distribution. Electrodiagnostic tests were negative. Segmental cervicothoracic motion dysfunctions were present which were regarded as contributing factors hindering natural recovery. Intervention and Outcomes: After 6 sessions consisting of nerve-gliding techniques and segmental joint manipulation and a home exercise program consisting of nerve gliding and light free-weight exercises, a substantial improvement was recorded on both the impairment and functional level (pain scales, clinical tests, and Northwick Park Questionnaire). Symptoms did not recur within a 10-month follow-up period, and pain and disability had completely resolved. Conclusions: Movement-based management may be beneficial in the conservative management of cubital tunnel syndrome. As this intervention is in contrast with the traditional recommendation of immobilization, comparing the effects of both interventions in a systematic way is an essential next step to determine the optimal treatment of patients with cubital tunnel syndrome.

Parotidectomy: review of treatment and outcomes

Background: Parotidectomy is a common surgical procedure performed for a wide array of benign and malignant tumours. The aim of the present study was to review a single-institution experience with parotidectomy over a 10 year period. Methods: We retrospectively reviewed 170 patients who had parotidectomy performed. The preoperative investigations, clinicopathological parameters, perioperative morbidity and mortality were assessed. Results: One hundred and six (62%) of the patients were men. The mean age was 54 years (range 21-80). Indications for parotidectomy included benign tumour (44%), malignant tumour (42%), inflammatory parotid disease (7%) and miscellaneous (5%). The most common benign tumour was pleomorphic adenoma (25%). The most common malignant tumour was metastatic cutaneous squamous cell carcinoma (SCC) (19%). Fine needle aspiration cytology was performed in 83% patients with a sensitivity and specificity for benign tumours of 76% and 97%, respectively. The sensitivity and specificity for malignant tumours was 90% and 99%, respectively. One (0.6%) patient died in the postoperative period. Postoperative complications included wound infection (2.3%), wound haematoma (3.5%) and seroma (6.6%). Six patients (3.5%) developed temporary complete facial paresis, while 33 patients (20%) developed temporary partial facial palsy in the immediate postoperative period. The 2-year disease-free and disease-specific survival for those patients with metastatic cutaneous SCC were 75% and 76%, respectively. Conclusions: The most common indications for parotidectomy were pleomorphic adenoma and metastatic cutaneous SCC. Our perioperative morbidity and survival for patients with malignant parotid disease compare favourably with other institutional series.

Effect of prolonged inactivity on skeletal motor nerve terminals during aestivation in the burrowing frog, Cyclorana alboguttata

This study examined the effect of prolonged inactivity, associated with aestivation, on neuromuscular transmission in the green-striped burrowing frog, Cyclorana alboguttata. We compared the structure and function of the neuromuscular junctions on the iliofibularis muscle from active C. alboguttata and from C. alboguttata that had been aestivating for 6 months. Despite the prolonged period of immobility, there was no significant difference in the shape of the terminals (primary, secondary or tertiary branches) or the length of primary terminal branches between aestivators and non-aestivators. Furthermore, there was no significant difference in the membrane potentials of muscle fibres or in miniature end plate potential (EPP) frequency and amplitude. However, there was a significant decrease in evoked transmitter release characterised by a 56% decrease in mean EPP amplitude, and a 29% increase in the failure rate of nerve terminal action potentials to evoke transmitter release. The impact of this suite of neuromuscular characteristics on the locomotor performance of emergent frogs is discussed.

Prediction of height from knee height in children with cerebral palsy and non-disabled children

Measurement of height or length is essential in the assessment of nutritional status. In some conditions, for example cerebral palsy (CP), such measurements may be difficult or impossible. Proxy measurements such as knee height have been used to predict height in such cases. We have evaluated two equations in the literature that predict stature from knee height in a group of 17 children with CP and 20 non-disabled children. The two equations performed well on average in the non-disabled children, with the mean predicted height being within 1% of the mean measured height. Nevertheless, the limits of agreement were relatively large. This was also the case for the children with CP. Thus the equations may be accurate at the group level; however they may lead to unacceptable error at the individual level. © 2006 Informa UK Ltd.

Lesch-Nyhan disease in a 20-year-old man incorrectly described as developing 'cerebral palsy' after general anaesthesia in infancy

Lesch–Nyhan disease (LND) is a rare X-linked recessive genetic disorder caused by a deficiency of hypoxanthine-guanine phosphoribosyltransferase (HPRT) enzyme. The classic clinical condition is characterized by cognitive impairment, hypotonia at rest, choreoathetosis, hyperuricaemia and the hallmark symptom of severe and involuntary self-mutilation. We describe a man with LND who was initially thought to have suffered from a dyskinetic cerebral palsy after an uncomplicated inguinal herniorrhaphy under general anaesthesia at 5 1/2 months of age. In the absence of overt self-injurious behaviour, the diagnosis was not considered for nearly two decades. The diagnosis of LND was established at 20 years of age through clinical review, biochemical examinations and molecular analysis. HPRT haemolysate activity was 7.6% of the normal control, suggesting that he had a milder variant of the disease. Mutation analysis of the HPRT gene revealed a novel missense mutation, c.449T > G in exon 6 (p.V150G). Cascade testing of family members revealed that the mother was heterozygous for the mutation but two siblings (a brother and a sister) did not carry the sequence mutation. Whether the onset of neurological abnormalities in this particular case can be attributed to the general anaesthesia is discussed.